Electric switch



Dec. 26, 1950 c. F. ROBBINS 2,535,151

ELECTRIC SWITCH Filed April 8, 1946 4 Sheets-Sheet).

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C. F. ROBBINS ELECTRIC SWITCH Dec. 26, 1950 Filed April 8, 1946 4 Sheets-Sheet 2 l 55 I6 57 M30542.

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20 Claims. 1

This invention relates to improvements in electric switches. and more particularly to manually operable, rotary shaft actuated, multiple-circuit controlling switches.

A primary object of the invention is to improve and simplify the construction, assembly and operation of the parts of such switches.

Another object is to minimize the size of such switches while insuring a relatively high current controlling capacity thereof, as compared with similar switches of the prior art.

Another object is to provide for use of a minimum number of diflerent parts to enable production of switches of various diferent electrical circuit controlling characteristics.

Another object is to provide a novel form of rotatable shaft for actuating the movable contactors of the switch.

Another object is to provide resilient means of novel form for indexing or positioning the actuating shaft in each of its predetermined rotary positions.

Another object is to provide a novel form of magnetic blowout and novel mounting means therefor, when the switch is to be employed for control of a direct current circuit or circuits.

Another object is to provide an operatng knob of novel form, and novel means for quickly and rigidly attaching the same removably to the actuating shaft.

Another object is to provide combined stationary contact and terminal members of novel form, and novel supporting means therefor.

Another object is to provide a. novel form of one-piece molded insulating base which is common to all forms of the switch herein illustrated.

Another object is to provide novel cooperating means formed integrally with the base and the shaft to alternatively produce switches of the twoposition or three-position type.

Another object is to provide a switch of the aforementioned character having contactors spring-based toward circuit completing position and positively movable to circuit interrupting position.

Various other objects and advantages of the invention will hereinafter appear.

The accompanying drawings illustrate certain preferred forms of switchesembodying my invention; it being understood that the invention is susceptible of embodiment in other forms within the scope of the appended claims.

In the drawings, Figure 1 is a top plan view, actual size, of a three-position, three terminal, direct current switch constructed in accordance with my invention; the manual operating knob being omitted for purposes of illustration.

Fig. 2 is a bottom plan view of the switch shown in Fig. 1. I

Fig. 3 is a central vertical section, double-scale, on the line 3-3 of Fig. l; certain of the parts being shown in elevation.

Fig. 4 is a central vertical section, on the line 44 of Fig. 1.

Fig. 5 is a plan view with the bottom cover plate removed; the securing bolts and certain of thestationary contact elements being shown in section.

Fig. 6 is a horizontal sectional view, on the line 66 of Fig. 4; the actuating shaft and the contactors being shown in elevation, and the indexing or posit;onin spring being shown in dotted lines.

Fig. '7 is a bottom plan view of the one-piece base adapted to be produced by a straight-line molding operation.

Fig. 8 is a plan view of the upper left-hand stationary contact and the upper right-hand stationary contact and terminal member shown in Fig. 6, illustrating the relative position of the bus member and the manner of attaching the latter; the points of bending of the bus member being shown by dotted lines.

Fig. 9 is a top plan view of the actuating shaft employed in a switch of the three-position type, like that of Figs. 1 to 8; the relatively long segmental recess in the upper end wall of the base (for cooperation with the stop member on the shaft) being illustrated in dotted lines; and fragments of the slide members, for cooperation with the cam' portions on the shaft, being also illustrated in dotted lines.

Fig. is a view similar to Fig. 9, but showing a shaft having a modified form of cam portions for cooperation with the slide members to provide a switch of the two-position type; the stop member on the shaft being displaced one hundred and eighty degrees for cooperation with the relatively shorter segmental recess, as indicated in dotted lines, and

Fig. 11 is a bottom plan view of a two-positio switch like that provided by the means illustrated inFig. 10.

Referring to Figs. 1 to 9 of the drawings, the numeral l0 designates a one-piece insulating base adapted to be produced by a straight-line molding operation. Base I0 is preferably hot molded to the form illustrated from a suitable material, such as Bakelite; although other hot moldable or cold moldable materials might be employed if de- 3 sired. Base II is of approximately rectangular contour and is provided with a recess II which opens to the lower end thereof; said recess havinga peripheral wall I! of substantial thickness, as best illustrated in Figs. 3, 4 and 6. Wall is is provided at its lower end with an upwardly offset inner ledge l8, against which a flat, punched insulating cover plate is (Figs. 2, 3 and 4) is adapted to seat in a relationship substantially flush with the lower end of base It.

Formed integrally with the upper end wall and one of the side walls of recess II is an abutment portion Ii of the contour best illustrated in Fig. 7; the flat lower surface of portion is being located in the plane of ledge It, as illustrated in ligs. 4, 5 and I. Also formed integrally with the upper end wall of recess. ll. opposite to abutment II, are three abutment portions ll, l1 and II (Figs. 6 and 7) whose lower end surfaces are likewise located in the plane of ledge ll. Bolt passages II and 20 extend vertically upwardly through the abutment I5 and the abutment II, respectively, and through the upper end wall of recess l I the upper surface of base It having circular countersinks II and 22 (Fig. 4) formed therein to accommodate the cylindrical lower end portions ll, 23 of a pair of like nuts, the square upper end portions 23, 23- of which are each adapted to have any two adjacent sides thereof seated laterally against a pair of right-angled shoulders Itv and II formed upon-abutmerits i0. Ill formed integrally with base It at said upper surface thereof (Fig. 1). The arrangement is preferably such that the square upper end portions 23' of said nuts will be flush with (Fig. 4) or slightly below the flat upper surfaces of abutments l0, Ill= when the switch parts are assembled. A pair of bolts 14, 24 have their threaded shanks extending upwardly through clearance rpenings provided in bottom cover plate l4 and through passages l9 and 20 to take into the portions 23, 23 of the respective nuts; the heads 24-, 24 of said bolts being preferably surrounded by inverted cup-shaped insulating washers It, 25, to prevent accidental contact of the circuit wires therewith (Figs. 2 and 4) As shown in Fig. 4, split lock washers 2'' are preferably interposed between the heads of said bolts and said washers 25. The threads in said nuts likewise extend entirely through the square portions 23, to accommodate the shanks of bolts (not shown) for attaching the switch as a whole to a. panel or other suitable support.

As shown in Figs. 1 and 4, the end portions 28' of said nuts are adapted to overlie and clamp the side edges of a rectangular flat plate 28 of nonmagnetic material, such as brass; the upper surface of base It being recessed at Hid to accommodate said plate in a substantially flush relation to the main portion of said surface (see Fig. 3 The upper surface of base is is further provided, at opposite ends of plate It with a pair of recangular recesses l0 and it each of which is adapted to accommodate a permanent magnet of the so-called Alnico type. as shown at 21, 21 in Fig. 3. As indicated by dotted lines in Figs. 1 and 3 the magnets 21' are provided at opposite ends thereof with rectangular portions of reduced thickness; the magnets being seated in recesses II and II with the full areas thereof facing downwardly and with the offset and portions thereof facing upwardly. In practice the magnets 21 are required only when the switch mechanism is employed for control of direct current circuits (of 600 volts maximum) as, for instance, the circuits of driving motors in refrigerating systerns. When the switch is employed for centre of alternating current power circuits having the aforementioned maximum voltage, or for control of pilot circuits (either alternating or direct current) the use of such permanent magnet blowouts is not necessary. In practice the non-magnetic plate as will be assembled as shown regardless of whether or not the magnets are employed.

Plate 20 is provided with a central circular opening 26- which is adapted to accommodate the integral cylindrical projection HI on base Ill; said projection and the upper end wall of recess ll having a central opening or passage I therethrough of circular cross section to provide a bearing for the cylindrical insulating portion II of the rotatable operating shaft 28 of the switch (Fig. 4). The portion 28" of shaft ll (from a point flush with the upper end of insulating portion II) is preferably of greater diameter than the lower portion of said shaft; and portion 20'' is also preferably flatted at one side thereof, as indicated at 28, for cooperation with known forms of operating knobs having recesses of corresponding form in transverse cross section, to provide for securement of the knob by means of a set screw orthe like. However. when a knob like that shown at 29 is to be attached, shaft portion 28 is provided at a predetermined point adjacent the upper end thereof with a transverse passage, shown in dotted lines at 28 in Fig. 4. Thus the manual operating knob 20 is of a suitable shape, illustrated in Figs. 3 and 4; the

same being provided with a cylindrical recess 29- (Fig. 4) to freely accommodate shaft portion 28 Knob 29 is shown as molded from a suit-1 able insulating material, such as Bakelite; but it is to be understood that the same might be die cast to the form illustrated from a suitable metal. Knob 29 is provided with a passage 28'' which penetrates the recess 29 for insertion of a pin 30, which is bent to the shape illustrated from a suitable length of wire composed of a suitable metal such as steel. When pin 30 is positioned as illustrated in Fig. 4, it will be seen that knob 29 is restrained against movement in any direction with respect to shaft portion 2'". Wire II is preferably provided with additional portions III, I0" and 30, each bent at right angles to its adjacent portion, and all of said portions being located in a common plane, Knob 29 is grooved or recessed as shown at 29, 29 and 28 to accommodate the respective portions 30', I0" and 30 aforementioned; the groove 29* being of gradually decreasing depth until it opens to the recess IO. By this means the wire clip or fastener may be moved laterally toward the final position thereof illustrated; the clip portion 10 being accommodated by groove 28 during insertion of pin portion Ill through passages 29' and until said clip portion Ill snaps into recess 18 to securely but removably retain the clip in assembled relation to knob 23 and shaft portion 2".

As shown in Fig. 7 the end :wall of recess Ii is provided with two sub-recesses II and II", respectively, of arcuate or segmental form, the inner edge of each of which communicates with the aforementioned bearing opening It. Recesses II' and H have vertical end walls ll and II, respectively, which are in diametrical alinement across the aforementioned bearing opening lll Recess H is adapted to accommodate a radial projection 28' of segmental form which is'molded integrally with the insulating [5 portion II of the operating shaft; the relative arcuate lengths of recess H and projection 28' being such as to provide for rotation of shaft 28 to any one of three equally spaced angular positions, as hereinafter described, when a switch of the three-position type illustrated'in Figs. 1 to 9, inclusive, is desired or required. Recess ll is utilized when a switch of the two-position type is provided, as hereinafter described.

Formed integrally with and in a plane below the operative portion of projection 28 is an insulating starwheel formation 28*; the hills of which and the valleys of which are diametrically opposed to each other, for-cooperation jointly with the V-shaped free end portions of the resilient arms of an approximately U-shaped spring member 8|, best illustrated in dotted lines in Fig. 6; the connecting portion of said spring II being positioned between abutment portion l1 and the adjacent portion of the peripheral wall 12.

In a plane below the star-wheel portion 28', and formed integrally therewith, are a pair of radially projecting cam portions 28' and 28; the cam portion 28' being relatively shorter than portion 28, as shown in Figs. 5 and 6; the initial operating edge 28 of the former being offset backwardly, as compared with the initial operating edge 28 of cam portion 28".

As shown in Figs. 3 to 6, the cam portions 28' and 28 are adapted to overlie the bottom portions 32*, 32 f a pair of like molded insulating slide members, which are complementally widened at 32, 32' (Figs. and 6), so that each relatively wide portion 32 and the adjacent relatively narrow portion of the other member are slidable between the vertical walls II, l5 of abutment IS, on one side, and the vertical walls i8 and It'- of abutments l6 and 18, on the other side. Said slide members are respectively provided with vertical cam portions 32, 32, which are adapted to be engaged sequentially by the aforementioned cam edges 28 and 28 As best illustrated in Fig. 3, each slide member is provided with a vertical portion 32 so that the outer ends of said slides are slidable between and guided by the end wall of recess II and the cover plate I. Each slide member is provided with a laterally opening cylindrical pocket 32 (Figs. 3 and 6) between th end wall of which and a side wall of recess II a coiled spring 83 is interposed under a predetermined degree of compression. Said side walls of recess II are provided with like grooves I2, I 2 with vertical ribs or ridges on opposite sides thereof (Figs. 3, 5 and 6) to facilitate insertion of the slide members and springs 88 into recess II and to prevent lateral displacement of said springs after the switch parts are assembled. The springs 88, 88 thus normally act to bias each slide member inwardly toward the axial center of shaft 28; the latter having a central cylindrical insulating portion 28 (Figs. 3 to 5) which is adapted to rotatably bear against the inner surface of cover plate ll.

Each slide member is provided at its outer end with a horizontal groove 32' (Fig. 3) to accommodate a substantially non-flexible bridging contactor 34; each contactor being attached by a headed rivet 84 or the like in such manner as to provide a slight degree of rocking or self-adjusting movement of the contactor when moved into engagement with a pair of stationary contacts.

In the three-position switch of Figs. 1 to 9 I prefer to employ three combined stationary contact and terminal members 85; the fourth stationary contact 35* being like the others, except that the wiring terminal portion thereof is cut away or omitted, as best illustrated in Fig. 8. Each stationary contact has a tip 28 of silver or silver base material rigidly and permanently attached thereto, and each contactor has a pair of such tips 36 attached thereto (Figs. 5 and 6). The stationary contacts 35 and 85* have rectangular end portions adapted to fit within pockets H, II, II and ll formed in the end wall of recess ll (Fig. 7). In practice the lower combined stationary contact and terminal member 85 (Fig. 5) is permanently electrically connected, by means of a metal strip or bus member 31, to contact 35, so that the wiring terminal associated with contact 35 will likewise provide a circuit connection for contact 85*. As shown in Figs. 4, 5 and 6, the bus member 81 is accommodated between abutment l1 and the adjacent side wall of recess ll, below the aforementioned spring ll.

' As shown in Fig. 4, the portion 28 of the operating shaft is preferably provided with a pair of integral lugs 28 and 28 pinched or gouged therefrom by a die forming operation, to provide a more positive connection or interlock between the same and the aforementioned insulating portions simultaneously molded thereabout. In practice the shaft 28 is die formed under pressure from a suitable length of soft steel wire; the portion 28 thereof being deformed or shapedas illustrated simultaneously with the formation of 28 and 28 aforementioned. In this manner I am enabled to obtain the special form of the shaft without the necessity for the usual expensive machining operation.

The portions till and 30 of the knob-securing clip are at or extend to the narrow end of knob 29, thus cooperating with the latter and with any suitable indicating plate to indicate the circuit controlling positions of the switch contactors.

With reference to Figs. 5 and 6, it will be apparent that upon continued rotary movement of the operating shaft (clockwise in Fig. 5, counterclockwise in Fig. 6) the cam edge 28 will engage the cam edge 32 of its associated Slide member to effect disengagement of the right-hand contactor 84 from its associated contacts, the lefthand contactor in said figures remaining disengaged. Upon reverse rotation of said shaft the right-hand and left-hand contactors will sequentially engage their associated pairs of stationary contacts. The manner in which two branch circuits, having one circuit terminal common thereto, are controlled will be apparent to those skilled in the art. Obviously, of course, a combined contact and terminal member 35 might be substituted for the contact member 35 (and the bus member 81 omitted) to provide for sequential completion and interruption of two electric circuits entirely separate from each other.

In Figs. 10 and 11, I have illustrated a modification wherein a two-position, two-circuit-controlling, on and "off" switch is provided. That is to say, the rotary shaft in one of its angular positions is adapted to provide for completion of two different circuits, and said shaftwhen rotated to its only other angular position is adapted to effect substantially simultaneous interruption of said circuits. In such a switch the base [0 may be identical with that aforedescribed, and four of the aforementioned combined stationary contact and terminal members 35 are employed, and no bus connections are provided between the latter.

The metal shaft 28 (Fig. 10) has molded thereon the insulating bearing portion 28* and the stop 7 projection II in the same relationship to the vertical flat surface 2l of shaft portion 28" as in the switch of Figs. 1 to 9. However, the integral insuiating star-wheel portion 28 in Fig. preferably has seven valleys or indentations formed therein, whereas the star-wheel portion 2" aforedescribed had six indentations. A pair of diametrically c-pposed cam portions II and II (like the aforementioned cam portion 28 have edges II and II adapted to substantially simultaneously engage with the respective cam edges 32, 32 of the aforementioned insulating slide members, to provide for coincident movement of the 8 jacent the outer ends of the latter. two pairs of stationary contacts into engagement with which said contactors are normally biased by said ,.--"and each of said stationary contacts having a pair of bridging contactors 34, 3| out .of engagement with their associated sets of stationary contacts, upon rotation of the shaft to one of its two angular positions; the contactors, of course being simultaneously re-engaged with their associated contacts upon reverse rotation of the shaft to its other angular position.

I claim:

1. In an electric switch, in combination, a molded insulating base having a recess opening to one end thereof, the end wall of said recess having a bearing opening formed therein, a shaft insertable through said recess and having a portion adapted to rotatably -flt within said bearing opening, said shaft having a plurality of radially projecting cam portions thereon, a pair of like insulating slide members arranged on opposite sides of said shaft,-said slide members being shaped with respect to each other and with respect to the recess walls to provide for substantially rectilinear movement of one or both of said slide members upon a given degree of rotary movement of said shaft, a pair of coiled compression springs respectively interposedbetween the outer ends of said slide members and the adjacent side walls of said recess, whereby said slide members are at all times biased toward the axial center of said shaft, a bridging contactor attached to one of said slide members adjacent the v outer end of the latter, a pair of stationary contacts into engagement with which said contactor is normally biased by its associated spring, said one of said cam portions coacting with its associated slide member to effect forcible disengagement of said contactor from said contacts as an incident to rotary movement of said shaft in one 7 direction, and an insulating cover member. secured to the open end of said recess, said cover member acting to retain said switch parts in assembled relationship to each other and to said base.

2. In an electric switch, in combination, a molded insulating base having a recess opening to the lower end thereof, the upper end wall of said recess having a bearing opening formed therein, a shaft insertable through said recess and having a portion adapted to rotatably fit within said bearing opening, said shaft having a plurality of radially projecting cam portions thereon, a pair of like insulating slide members arranged on opposite sides of said shaft, said slide members being shaped with respect to each other and with respect to the recess walls to provide for substantially' rectilinear movement of one or both of said slide members upon a given degree of rotary movement of said shaft, 9. pair of coiled compression springs respectively interposed between the outer ends of said slide members and the adjacent side walls of said recess, whereby said slide members are at all times biased toward the axial center of said shaft, a pair of bridging.contactors respectively attached to said slide members admolded insulatingbase having a recess opening to the lower end thereof, the upper end wall of said recess having a bearing opening formed therein, a shaft insertable upwardly through said recess and having a portion adapted to rotatably fit within said bearing opening, said shaft having a plurality of radially projecting cam portions thereon, a pair of like insulating slide members arranged 'on opposite sides of said shaft, said slide members being shaped with respect to each other and with respect to the recess walls to provide for. substantially rectilinear movement of one or both of said slide members upon a given degree of rotary movement of said shaft. a pair of coiled compression springs respectively interposed between the outer ends of said slide members and the adjacent side walls of said recess, whereby said slide members are at all times biased toward the axial center of said shaft, a pair of bridging contactors respectively attached to said slide members adjacent the outer ends of the latter, two pairs of stationary contacts into engagement with which said contactors are normally biased by said springs, said cam portions coacting with said slide members to effect forcible disengagement of said contactors from said contacts as an incident to rotary movement of said shaft in one direction, an insulating cover member secured to the lower end of said recess, said cover member acting to retain said switch parts in assembled relationship to each other and to said base, said cover member having four openings formed therein, each of said stationary contacts having a reduced portion adapted to project outwardly through one of said openings, each reduced portion forming at least one shoulder which said cover member is adapted to underlie, and certain of said reduced portions having wiring terminal elements formed integrally therewith to provide for attachment of circuit wires.

4. In an electric switch, in combination, a molded insulating base having a recess opening to the lower end thereof, the upper end wall of said recess having a bearing opening formed therein, a shaft insertable upwardly through respectively interposed between the outer ends of said slide members and the adjacent side walls of said recess, whereby said slide members are at all times biased toward the axial center of said shaft, a pair of bridging contactors respectively attached to said slide members adjacent the outer ends of the latter, two pairs of stationary contacts into engagement with which said contactors are normally biased by said springs, said cam portions coacting with said slide members to effect forcible. disengagement of said contactors from said contacts as an incident to rotary movement of said shaft in one direction, an insulating cover member secured to the lower end of said recess, said cover memher acting to retain said switch parts in assembled relationship to each other and to said base, said cover member having four openings formed therein, each of said stationary contacts having a reduced portion adapted to project outwardly through one of said openings, each reduced portion forming at least one shoulder which said cover member is adapted to underlie, certain of said reduced portions having wiring terminal elements formed integrally therewith to provide for attachment of circuit wires, and cooperating means formed integrally with said base and said shaft respectively to positively limit the range of rotary movement of the latter.

5. In an electric switch, in combination, a onepiece insulating base adapted to be produced by a straight line molding operation, said base having a recess formed therein and opening to the lower surface thereof, the upper end wall of said recess having a bearing opening formed therein, switch mechanism including a rotatable shaft insertable into said recess and having bearing engagement with said opening, two pairs of pockets formed in the upper end wall of said recess, a corresponding number of substantially rigid stationary contacts seated within the respective pockets, contact tips attached to the respective contacts at like points between the upper and lower ends of said recess, said shaft having a reduced lower end portion and a pair of radially projecting cam portions directly thereabove, a pair of like but oppositely arranged insulating slide members each having a relatively wide portion adjacent the outer end thereof and a relatively narrow portion projecting therefrom for sliding clearance with respect to the relatively wide portion of the other member, said slide members having reciprocating clearance with respect to said lower end portion of the shaft, coiled compression springsinterposed between the outer ends of the respective slide members and the adjacent walls of said recess to normally bias said slide members toward the axial center of said shaft, a substantially rigid bridging contactor attached to the outer end of each slide member and having a predetermined degree of lost motion with respect thereto, tips attached to said contactors for cooperation with the stationary contact tips aforementioned, said slide members having portions formed for cooperation with said cam portions to provide for simul taneous or sequential disengagement and engagement of said contactor tips with respect to said contact tips, according to the form of said cam portions, and an insulating cover member attached to said base and overlying the lower end of said recess to retain all of said switch parts in assembled relationship to each other and to said base.

6. In an electric switch, in combination, a onepiece insulating base adapted to be produced by a straight line molding operation, said base having a recess formed therein and opening to the lower surface thereof, the upper end wall of said recess having a bearing opening formed therein, switch mechanism including a rotatable shaft insertable into said recess and having bearlns engagement with said opening, two pairs of pockets formed in the upper end wall of said recess, a corresponding number of substantially rigid stationary contacts seated within the respective pockets, contact tips attached to the respective contacts at like points between the upper and lower ends of said recess, said shaft having a reduced lower end portion and a pair of radially projecting cam portions directly thereabove, a pair of like but oppositely arranged insulating slide members each having a relatively wide por-- tion adjacent the outer end thereof and a roletively narrow portion projecting therefrom for sliding clearance with respect to the relatively wide portion of the other member, said slide members having reciprocating clearance with re-- spect to said lower end portion of the shaft, coiled compression springs interposed between the outer ends of the respective slide members and the adjacent walls of said recess to normally bias said slide members toward the axial center of said shaft, a substantially rigid bridging contactor attached to the outer end of each slide member and having a predetermined degree of lost motion with respect thereto, tips attached to said contactors for cooperation with the stationary contact tips aforementioned, said slide members having portions formed for cooperation with said cam portions to provide for simultaneous or sequential disengagement and engagement of said contactor tips with respect to said contact tips, according to the form of said cam portions, an insulating cover member attached to said base and overlying the lower end of said recess to retain all of said switch parts in assembled relationship to each other and to said base, and cooperating means formed integrally with said base and said shaft respectively to positively limit the degree of rotation of the latter.

'7. In an electric switch. in combination, a onepiece insulating base adapted to be produced by a straight line molding operation, said base having a recess formed therein and opening to the lower surface thereof, the upper end wall of said recess having a bearing opening formed therein, switch mechanism including a rotatable shaft insertable into said recess and having bearing engagement with said opening, two pairs of pockets formed in the upper end wall of said recess, a corresponding number of substantially rigid stationary contacts seated within the respective" pockets, contact tips attached to the respective contacts at like points between the upper and-'- lower ends of said recess, said shaft having a reduced lower end portion and a pair of radially projecting cam portions directly thereabove,apair of like but oppositely arranged insulating slide members each having a relatively wide portion adjacent the outer end thereof and a relatively narrow portion projecting therefrom for sliding clearance with respect to the relatively wide portion of the other member, said slide members having reciprocating clearance with respect to said lower end portion of the shaft, coiled compression springs interposed between the outer ends of the respective slide members and the adjacent walls of said recess to normally bias said slide members toward the axial center of said shaft, a substantially rigid bridging contactor attached to the outer end of each slide member and having a predetermined degree of lost motion with respect thereto, tips attached to said contactors for cooperation with the stationary contact tips aforementioned, said slide members having portions formed for cooperation with said cam portions to provide for simultaneous or sequential disengagement and engagement of said contactor tips with respect to said contact tips, according to the form of said cam portions, an insulating cover member attached to said base and overlying the lower end of said recess to retain all of said switch parts in assembled relationship to each other and to said base, cooperating means formed integrally with said base and said shaft respectively to positively limit the degree of rotation of the latter, said shalt having a star-wheel formation thereon, and a. substantially U-shaped spring retained in position by said base and said shaft, said spring having inwardly and then outwardly bent free end portions respectively adapted to engage diametrically opposite portions of said starwheel to insure attainment of a definite rotary position of the shaft upon manual release thereof.

8. In an electric switch, in combination, a recessed molded insulating base, a cover member attached to said base and overlying the recess, a pair of molded insulating members interposed between said cover member and the opposed wall of said recess for sliding movement relatively thereto, certain walls of said recess having spaced parallel abutments formed integrally therewith, said insulating members being so shaped with respect to said abutments and with respect to each other as to insure rectilinear sliding movement thereoi, a coiled compression spring interposed between the outer end of each insulating member and an adjacent wall of said recess to normally bias said members toward each other in laterally overlapping relationship, each of said members having 9, lug formed integrall therewith in spaced relation to said cover member, a shaft rotatably supported within said recess, said shaft having a pair of cam portions thereon for cooperation with said lugs respectively, whereby upon a, given degree of rotation of said shaft in one direction one or both of said insulating members will be moved outwardly from said shaft against the bias of its associated spring, according to the form of the respective cam portions, a bridging contactor non-rotatably attached to the outer end of each insulating member but having a predetermined degree of tiltable lost motion with respect thereto, two pairs of combined stationary contact and terminal members carried by said base within said recess and into and out of engagement with which said contactors are respectively adapted to move, said cover member acting to retain all of said switch parts in assembled relationship to said base.

9. In a rotary electric switch, in combination, a one-piece molded insulating base having a recess opening to the lower end thereof, the upper end wall of said recess having a bearing opening formed therein centrally thereof, a shaft insertable into said recess and having a portion formed of insulating material adapted to bear within said opening, said shaft also having a star-wheel portion and a pair of cam portions formed integrally with said portion first mentioned, a, substantially U-shaped spring interlocked with said base and said shaft for cooperation with said star-wheel portion on opposite sides of the latter, a pair of insulating slide members having portions underlying said cam portions and vertical shoulders .to be respectively engaged with the latter, spring means for continuously biasing said vertical shoulders toward the respective cam portions. a pair of bridging contactors respectively attached to the slide members at the outer ends of the latter and adapted to have a predetermined degree oi tilting movement relatively thereto, two pairs of stationary contacts seated in said recess and into and out of engagement with which said contactors are respectively adapted to be moved upon predetermined degrees of rotary movement of said shaft in opposite directions, and a flat plate of insulating material secured to said base at the lower end of said recess, said plate cooperating with said base to retain all of said switch parts in assembled relation.

10. In a rotary electric switch, in combination, a one-piece molded insulating base having a recess opening to the lower end thereof, the upper end wall of said recess having a bearing opening formed therein centrally thereof, a shaft insertable into said recess and having a portion formed of insulating material adapted to bear within said opening, said shaft also having a star-wheel portion and a pair of cam portions formed integrally with said portion first mentioned, a substantially U-shaped spring interlocked with said base and said shaft for cooperation with said star-wheel portion on opposite sides of the latter, a pair of insulating slide members having portions underlying said cam portions and vertical shoulders to be respectivel engaged with the latter, spring means for continuously biasing said vertical shoulders toward the respective cam portions, 0. pair of bridging contactors respectively attached to the slide members at the outer ends of the latter and adapted to have a limited amount of lost motion relatively thereto, two pairs of stationary contacts seated in said recess and into and out of engagement with which said contactors are respectively adapted to be moved upon predetermined degrees of rotary movement of said shaft in opposite directions, a flat plate of insulating material secured to'said base at the lower end of said recess, said plate cooperating with said base to retain all of said switch parts in assembled relation, and at least three of said stationary contacts having wiring terminal portions formed integrally therewith and projecting downwardly through said plate to provide attachment of circuit wires.

11. In a rotary electric switch, in combination, a one-piece molded insulating base having a recess opening to the lower end thereof, the upper end wall of said recess having a bearing opening formed therein centrally thereof, a shaft insertable into said recess and having a portion formed of insulating material adapted to bear within d peni said shaft also having a star-wheel portion and a pair of cam portions formed integrally with said portion first mentioned, a substantiall U-shaped spring interlocked with said base and said shaft for cooperation with said star-wheel portion on opposite sides of the latter, a pair of insulating slide members having portions underlying said cam portions and vertical shoulders to be respectively engaged with the latter, spring means for continuously biasing said vertical shoulders toward the respective cam portions, a pair of bridging contactors respectively attached to the slide members at the outer ends of the la ter and adapted to have a predetermined degree of tilting movement relativeb thereto, two

pairs of stationary contacts seated in said recess and into and out of engagement with which said contactors are respectively adapted to bemoved upon predetermined degrees of rotary movement of said shaft in opposite directions, a, flat plate of insulating material secured to said base at the lower end of said recess, said plate cooperating with said base to retain all of said switch parts in assembled relation, said shaft including a metal portion projecting upwardly beyond said base, said shaft portion having an Opening extending transversely therethrough, a molded insulating knob having a recess formed therein to accommodate the upper end of said shaft portion, said knob having a transversely extending recess to be alined with the opening in said shaft portion to provide for insertion of a securing pin, and said pin having a reilexed clip portion formed integrally therewith for interlocking with another portion of said knob to prevent accidental displacement of said pin.

12. In a rotary electrical switch, in combination, a one-piece molded insulating base having a recess opening to the lower end thereof, the upper end wall of said recess having a bearing opening formed therein centrally thereof, a shaft insertable into said recess and having a portion formed of insulating material adapted to bear within said opening, said shaft also having a starwheel portion and a pair of cam portions formed integrally with said portion first mentioned, a substantially u-shaped spring interlocked with said base and said shaft for cooperation with said star-wheel portion on opposite sides of the latter, a pair of insulating slide members having portions underlying said cam portions and vertical shoulders to be respectively engaged with the latter, spring means for continuously biasing said vertical shoulders toward the respective cam portions, a pair of bridging contactors respectively attached to the slide members at the outer ends of the latter andadapted to.have a predetermined degree of tilting movement relatively, thereto, two pairs of stationary contacts seated in said recess and into and out of engagement with which said contactors are v respectively adapted to be moved upon predetermined degrees of rotary movement of said shaft in opposite directions, a flat plate of insulating material underlying the open end of said recess, and a pair of bolts penetrat ng said plate and said base, said bolts having threaded engagement with headed nuts at the upper surface of said base, whereby said insulating plate and all of said switch parts are retained in assembled relationship to said base.

13. In a rotary electric switch,'in combination, a one-piece molded insulating base having a recess opening to the lower end thereof, the upper end wall of said recess having a bearing opening formed therein centrally thereof, a shaft insertable into said recess and having a portion formed of insulating material adapted to bear within said opening. sa d shaft also having a star-wheelportion anda pair of cam portions formed integrally with said portion first mentioned, a substantial U-shaped spring interlocked with said base and said shaft for cooperation with said star-wheel portion on o posite sides of the latter, a pair of insulating slide members having portions underlying said cam portions and vertical shoulders to be respectively engaged with the latter, sprin means for continuously biasing said vertical shoulders toward the respective cam portions, a

pair of bridging contactors respectively attached to the slide members at the outer ends of the latter and adapted to have a predetermined degree of tilting movement relatively thereto, two pairs of stationary contacts seated in said recess inwardly of the respective contactors and into and out of engagement with which said contactors are respectively adapted to be moved upon predetermined degrees of rotary movement of said shaft in opposite directions, a flat plate of insulatingmaterial underlying the open end of said recess, a pair of bolts penetrating said plate and said base, said bolts having threaded engagement with headed nuts at the upper surface of said base, whereby said insulating plate and all of said switch parts are retained in assembled relationship to said base, a non-magnetic plate overlying a portion of the upper surface of said base and adapted to be clampingly engaged by the heads of said nuts, and a pair of permanent magnets underlying said last mentioned plate at opposite ends of the latter.

14. In a rotary electric switch, in combination, a one-piece molded insulating base having a recess opening to the lower end thereof, the upper l end wall of said-recess having a bearing opening formed therein centrally thereof, a shaft insertable into said recess and having a portion formed of insulating material adapted to bear within said opening, said shaft also having a star-wheel portion and a pair of cam portions formed integrally with said portion first mentioned. a sub stantially U-shaped spring interlocked with said base and said shaft for cooperation with said star-wheel portion on opposite sides of the latter, a pair of insulating slide members having portions underlying said cam portions and vertical shoulders to be respectively engaged with the latter. spring means for cont nuously biasing said vertical shoulders toward the respective cam portions, a pair of bridging contactors respectively attached to the slide members at the outer ends of the latter and adapted to have a predetermined degree of tilting movement relatively thereto, two pairs of stationary contacts seated in said recess and into and out of engagement with which said contactors are respectively adapted to be moved upon predetermined degrees of rotary movement of said shaft in opposite directions, a flat plate of insulating material secured to said base at the lower end of said recess. said plate cooperating with said base to retain all of said switch parts in assembled relation, a radial-sided stud formed inte rally with the first mentioned insulating portion of said shaft, and an arcuate depression formed in the upper end wall of said recess to accommodate said stud, said depression having rad al end walls to be en aged by the respective radial sides of said stud to positively limit the maximum amount of rotation of said shaft. 1

15. In a rotary electric switch. in combination, a one-piece molded insulating base having a recess opening to the lower end thereof. the unper end wall of said recess having a bearin onening formed therein centrally thereof, ashaft insertable into said recess and having a portion formed of insulating material adapted to bear within said opening, said shaft also having a starwheel portion and a pair of cam portions formed integrally with said portion first mentioned a substantially U-shaped spring interlocked with said base and said shaft for cooperation with said star-wheel portion on opposite sides of the latter, a pair of insulating slide members having portions underlying said cam portions and vertical gunner shoulders to be respectively engaged with the latter, spring means for continuously biasing said vertical shoulders toward the respective cam portions, a pair of bridging contactors respectively attached to the slide members at the outer ends of the latter and adapted to have a predetermined degree of tilting movement relatively thereto, two pairs of stationary contacts seated in said recess and into and out of engagement with which said contactors are respectively adapted to be moved upon predetermined degrees of rotary movement of said shaft in opposite directions, a flat plate of insulating material secured to said base at the lower end of said recess, said plate cooperating with said base to retain all of said switch parts in assembled relation, a radial-sided stud formed integrally with the first mentioned insulatin portion of said shaft, an arcuate depression formed in the upper end wall of said recess to accommodate said stud, said depression having radial end walls to be engaged by the respective radial sides of said stud to positively limit the maximum amount of rotation of said shaft, and a second depression of diiferent arcuate length also formed in the upper end wall of said recess. said last mentioned depression being adapted to alternatively accommodate a stud of the character aforementioned to afford a different maximum amount of rotation of said shaft.

16. In a rotary electric switch, in combination, a one-piece molded insulating base having a recess formed therein and opening to the lower end thereof, a fiat plate of insulating material underlying the open end of said recess, two pairs of stationary contacts each including a sheet metal punching, the upper end wall of said recess having pockets formed therein to respectively accommodate and position one end portion of each punching, said plate having a corresponding number of openings formed therein, said punchings having portions of reduced width extending downwardly from the plane of the inner surface of said plate through said openings, the horizontal shoulders on said punchings being adapted to seat against said plate, a pair of bridging contactors movable rectilinearly into and out of engagement with the respective pairs of contacts, a rotary shaft of insulating material having bearing engagement with said base and said plate and adapted upon rotation thereof to effect such movements of said contactors, a pair of permanent magnets positioned upon the upper surfaces of said base, the poles of each magnet being in substantially vertical alinement with the respective stationary contacts of a pair, a non-magnetic plate overlying both of said magnets, a pair of headed nuts the respective heads of which overlie opposite edge portions of said last mentioned plate, and a pair of bolts penetrating said insulating plateand said base and having threaded engagement with said nuts, to provide for retention of all of the aforementioned parts in assembled relation.

1'7. In a rotary electric switch, in combination, a one-piece molded insulating base having a recess formed therein and opening to the lower end thereof, a flat plate of insulating material underlying the open end of said recess, two pairs of stationary contacts each including a sheet metal punching, the upper end wall of said recess havin pockets formed therein to respectively accommodate and position one end portion-of each punching, said plate having a corresponding number of openings formed therein,

said punchings having portions of reducedwidth.

extending downwardly from the plane of the inner surface of said plate through said openings,

with the respective stationary contacts of a pair,

a non-magnetic plate overlying both of said magnets, a pair of headed nuts the respective heads of which overlie opposite edge portions of said last mentioned plate, a pair of bolts penetrating said insulating plate and said base and having threaded engagement with said nuts, to provide for retention of all of the aforementioned parts in assembled relation, and the head portions of said nuts having threads formed therein to accommodate the shanks of bolts adapted to secure the switch as a whole to a panel or similar support.

18. In a rotary electric switch, in combination, a one-piece molded insulating base having a recess formed therein and opening to the lower end thereof, a flat punched plate of insulating material underlying the open end of said recess, abutments formed integrally with said base to provide two pairs of vertical walls within said recess, two pairs of stationary contacts each including a. punched sheet metal member adapted to seat fiatwise against the respective vertical walls, the upper end wall of said recess having pockets formed therein to closely accommodate and position one end portion of each punching, said plate having a corresponding number of openings formed therein, said punchings having reduced end portions extending downwardly through said plate openings, a pair of bridging contactors positioned outwardly of the respective 19. In a rotary electric switch, in combination, a

a one-piece molded insulating base having a recess formed therein and opening to the lower end thereof. a flat punched plate of insulatin material underlying the open end of said recess, abutments formed integrally with said base to provide two pairs of vertical walls within said recess, two pairs of stationary contacts each including a punched sheet metal member adapted to seat fiatwise against the respective vertical walls, the up per end wall of said recess having pockets formed therein to closely accommodate and position one end portion of each punching, said plate having a corresponding number of openings formed therein, said punchings having reduced end portions extending downwardly through said plateout of bridging engagement with said pairs of contacts, said means comprising a rotary shaft an insulating portion of which has bearing engagement with said base and said plate, said shaft having an insulating portion in the form of a star-wheel, and a substantially U-shaped spring held captive within said recess, the free ends of the arms of said spring being shaped to cooperate with diametrically opposite portions of said starwheel to insure definite positioning of said shaft upon manual release of the latter.

20. In a rotar electric switch, in combination, a one-piece molded insulatin base having a recess formed therein and opening to the lower end thereof, a flat punched plate of insulating material underlying the open end of said recess, abutments formed integrally with said base to provide two pairs of vertical walls within said recess, two pairs of stationary contacts each including a punched sheet metal member adapted to seat flatwise against the respective vertical walls, the upper end wall of said recess having pockets formed therein to closely accommodate and position one end portion of each punching, said plate having a corresponding number of openings formed therein, said punchings having reduced end portions extending downwardly through said plate openings, a pair of bridging contactors positioned outwardly of .the respective pairs of stationary contacts and normally springbiased into engagement with the latter, means for positively effecting rectilinear bodily movement of said contactors out of bridging engagement with said pairs of contacts, said means comprising a rotary shaft an insulating portion of which has bearing engagement with said base and said plate, said shaft having an insulating portion in the form of a star-wheel, a substantially U-shaped spring held captive within said recess, the free ends of the arms of said spring being shaped to cooperate with diametrically opposite portions of said star-wheel to insure definite and positioning of said shaft upon manual release of the latter, and means comprising spaced insulating shoulders formed integral- 1y with said base and said shaft to positively limit the maximum degree of rotation of the latter in each direction.

CLYDE F. ROBBINS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,795,341 Marsh Mar. 10, 1931 1,995,671 Dashner Mar. 26, 1935 2,332,448 Heinrich Oct. 9, 1943 2,355,959 Dodd Aug. 15,1944 

